// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: http://codemirror.net/LICENSE

// Highlighting text that matches the selection
//
// Defines an option highlightSelectionMatches, which, when enabled,
// will style strings that match the selection throughout the
// document.
//
// The option can be set to true to simply enable it, or to a
// {minChars, style, wordsOnly, showToken, delay} object to explicitly
// configure it. minChars is the minimum amount of characters that should be
// selected for the behavior to occur, and style is the token style to
// apply to the matches. This will be prefixed by "cm-" to create an
// actual CSS class name. If wordsOnly is enabled, the matches will be
// highlighted only if the selected text is a word. showToken, when enabled,
// will cause the current token to be highlighted when nothing is selected.
// delay is used to specify how much time to wait, in milliseconds, before
// highlighting the matches. If annotateScrollbar is enabled, the occurences
// will be highlighted on the scrollbar via the matchesonscrollbar addon.

(function(mod) {
    if (typeof exports == "object" && typeof module == "object") // CommonJS
        mod(require("../../lib/codemirror"), require("./matchesonscrollbar"));
    else if (typeof define == "function" && define.amd) // AMD
        define(["../../lib/codemirror", "./matchesonscrollbar"], mod);
    else // Plain browser env
        mod(CodeMirror);
})(function(CodeMirror) {
    "use strict";

    var defaults = {
        style: "matchhighlight",
        minChars: 2,
        delay: 100,
        wordsOnly: false,
        annotateScrollbar: false,
        showToken: false,
        trim: true
    }

    function State(options) {
        this.options = {}
        for (var name in defaults)
            this.options[name] = (options && options.hasOwnProperty(name) ? options : defaults)[name]
        this.overlay = this.timeout = null;
        this.matchesonscroll = null;
        this.active = false;
    }

    CodeMirror.defineOption("highlightSelectionMatches", false, function(cm, val, old) {
        if (old && old != CodeMirror.Init) {
            removeOverlay(cm);
            clearTimeout(cm.state.matchHighlighter.timeout);
            cm.state.matchHighlighter = null;
            cm.off("cursorActivity", cursorActivity);
            cm.off("focus", onFocus)
        }
        if (val) {
            var state = cm.state.matchHighlighter = new State(val);
            if (cm.hasFocus()) {
                state.active = true
                highlightMatches(cm)
            } else {
                cm.on("focus", onFocus)
            }
            cm.on("cursorActivity", cursorActivity);
        }
    });

    function cursorActivity(cm) {
        var state = cm.state.matchHighlighter;
        if (state.active || cm.hasFocus()) scheduleHighlight(cm, state)
    }

    function onFocus(cm) {
        var state = cm.state.matchHighlighter
        if (!state.active) {
            state.active = true
            scheduleHighlight(cm, state)
        }
    }

    function scheduleHighlight(cm, state) {
        clearTimeout(state.timeout);
        state.timeout = setTimeout(function() {highlightMatches(cm);}, state.options.delay);
    }

    function addOverlay(cm, query, hasBoundary, style) {
        var state = cm.state.matchHighlighter;
        cm.addOverlay(state.overlay = makeOverlay(query, hasBoundary, style));
        if (state.options.annotateScrollbar && cm.showMatchesOnScrollbar) {
            var searchFor = hasBoundary ? new RegExp("\\b" + query + "\\b") : query;
            state.matchesonscroll = cm.showMatchesOnScrollbar(searchFor, false,
                {className: "CodeMirror-selection-highlight-scrollbar"});
        }
    }

    function removeOverlay(cm) {
        var state = cm.state.matchHighlighter;
        if (state.overlay) {
            cm.removeOverlay(state.overlay);
            state.overlay = null;
            if (state.matchesonscroll) {
                state.matchesonscroll.clear();
                state.matchesonscroll = null;
            }
        }
    }

    function highlightMatches(cm) {
        cm.operation(function() {
            var state = cm.state.matchHighlighter;
            removeOverlay(cm);
            if (!cm.somethingSelected() && state.options.showToken) {
                var re = state.options.showToken === true ? /[\w$]/ : state.options.showToken;
                var cur = cm.getCursor(), line = cm.getLine(cur.line), start = cur.ch, end = start;
                while (start && re.test(line.charAt(start - 1))) --start;
                while (end < line.length && re.test(line.charAt(end))) ++end;
                if (start < end)
                    addOverlay(cm, line.slice(start, end), re, state.options.style);
                return;
            }
            var from = cm.getCursor("from"), to = cm.getCursor("to");
            if (from.line != to.line) return;
            if (state.options.wordsOnly && !isWord(cm, from, to)) return;
            var selection = cm.getRange(from, to)
            if (state.options.trim) selection = selection.replace(/^\s+|\s+$/g, "")
            if (selection.length >= state.options.minChars)
                addOverlay(cm, selection, false, state.options.style);
        });
    }

    function isWord(cm, from, to) {
        var str = cm.getRange(from, to);
        if (str.match(/^\w+$/) !== null) {
            if (from.ch > 0) {
                var pos = {line: from.line, ch: from.ch - 1};
                var chr = cm.getRange(pos, from);
                if (chr.match(/\W/) === null) return false;
            }
            if (to.ch < cm.getLine(from.line).length) {
                var pos = {line: to.line, ch: to.ch + 1};
                var chr = cm.getRange(to, pos);
                if (chr.match(/\W/) === null) return false;
            }
            return true;
        } else return false;
    }

    function boundariesAround(stream, re) {
        return (!stream.start || !re.test(stream.string.charAt(stream.start - 1))) &&
            (stream.pos == stream.string.length || !re.test(stream.string.charAt(stream.pos)));
    }

    function makeOverlay(query, hasBoundary, style) {
        return {token: function(stream) {
            if (stream.match(query) &&
                (!hasBoundary || boundariesAround(stream, hasBoundary)))
                return style;
            stream.next();
            stream.skipTo(query.charAt(0)) || stream.skipToEnd();
        }};
    }
});